Transposition keyboard for pianos



Allg. 27, 1940- c. HAGsTRoM 2,213,087

TRANSPOSITION KEYBOARD FOR PIANOS Filed March 31, 1959 N la 5 15 0. 6 ,y 14 106 1713 14 9 'j 1.a 17

INVENTO R Carl xyzgSbzrom BY m mToRNEY Patented Aug. 27, 1940 UNITED STATES PATENT OFFICE 4 Claims.

This invention relates to new and useful improvements in a transposition keyboard for planos.

The invention has for an object the construction of a piano keyboard which is characterized by a specific arrangement by which the keys may be shifted into various lateral positions and held in these positions totranspose the keyboard.

Furthermore, it is proposed that the keys be associated with hammer mechanism which moves relative to the strings of the piano during the transposition mentioned.

Still further the invention proposes a novel arrangement for supporting the keys and the hammers and for moving these parts as desired.

Another object of this invention resides in a novel arrangement by which the keys may be shifted forwards or rearwards through predetermined distances to affect the hammer action for modulating the tone of the piano.

For further comprehension of the invention, and of the objects and advantages thereof, reference will be had to the following description and accompanying drawing, and to the appended claims in which the various novel features of the invention are more particularly set forth.

In the accompanying drawing forming a material part of this disclosure:

Fig, l is a fragmentary perspective View of a keyboard for a piano constructed according to this invention.

Fig. 2 is a fragmentary vertical sectional view taken on the line 2-2 of Fig. l, this view showing a portion of hammer mechanism and its particular relationship to the keys.

Fig. 3 is a fragmentary vertical sectional view taken on the line 3-3 of Fig. 2.

Fig. 4 is a plan view looking in the direction of the line 4 4 of Fig. 2.

Fig. 5 is a front elevational View of Fig. 2 with certain parts removed to disclose interior parts.

Fig. 6 is a bottom elevational view of a portion of the hammer mechanism and a portion of the strings of the piano.

Fig. '7 is a similar View to Fig. 2, but illustrating the modified form of the invention.

The transposition keyboard for pianos, according to this invention, includes a carrier I0 laterally slidably mounted in said piano and supporting a plurality of keys II and I2 which extend forwards and rearwards. The carrier It is supported by several rollers I3. These rollers are mounted upon brackets I4 mounted upon the bottom of the carrier. The brackets I4 ex- (Clf 84--447) tend into grooves' I5 formed in a frame portion I6 of the piano body. The rollers I3 engage in narrow grooves I'I formed in the bases of the grooves I5.

Guiding pins I8 are mounted upon the car- 5 rier III and extend into limiting grooves I9 formed in the frame I5 for limiting motion of the carrier laterally towards the right or the left as desired. The keys II and I2 are supported upon the carrier I0 by conventional vertical 10 pintles 2U. These pintles have small leaf springs 2I supported upon their upper ends and engaging the top faces of the keys for individually holding the keys in horizontal positions. The arrangement is such that the front ends of the 15 keys may be depressed so that the rear ends move upwards, and when the keys are released they seek normal horizontal positions. Stop pins 22 are mounted upon the carrier I and engage into recessed openings 23 formed in the 20 bottom faces of the keys to limit downward depression thereof.

An arrangement is provided for locking the carrier ID in various lateral positions. This arrangement includes a rod 25 pivotally mounted 25 to move up and down by a pintle 26 upon the carrier I and extending forwards. A bracket 21 is also mounted upon the carrier I!) and a tension spring 28 is connected between the bracket and the rod 25 for normally urging the 3() rod upwards. The rod 25 is provided with a head 29 at its outer end by which it may be manually moved. The rod 25 extends through an opening 30 formed in a plate 3i mounted upon the front of the piano. This opening 39 has a plu- 35 rality of recessed top branches 32 into which the rod 25 is urged by the spring 28. The arrangement is such that the rod 25 may be manually pivoted downwards to remove same from one of the branches 32, and then the rod may be moved laterally in one direction or the other, along the opening 30 to a new position. Then when the rod 25 is released it will move upwards and engage a dilerent one of the branch openings 32.

A hammer mechanism is associated with the keys. This hammer mechanism includes a transmission hammer 34 mounted on the inner end of each of the keys and cooperative with an operator hammer 35 pivotally supported by a 50 pintle 36 mounted upon a bracket 3l mounted on a frame 38. This frame 38 has a back plate 39 formed with slots 4D through which supporting elements 4I pass. These supporting elements 4I engage the body portion 42 of the piano body, 55

so that the frame 38, 39 is slidably supported. Rods i3 connect the frame 38, 33 with the carrier Iii (see Fig. 5) so that these parts' move in unison with each other. At the sides of the piano, at the keyboard area, there are cover plates 44 beneath which there is a recessed portion 45 into which the end keys of the keyboard may be moved when the keyboard is transposed in one direction or the other.

In Fig. 6 the operator hammers 35 are shown in specific relation to the strings It of the piano string board. It should be understood that when the keyboard is transposed the keys will move relative to the strings i6 and so there is a transposition of the keys of the piano.

In Fig. 7 a modified form of the invention has been disclosed which distinguishes from the prior form in the fact that an arrangement has been provided to modulate the hammer action of the piano. In this form of the invention the carrier lll consists of an upper layer tre and a lower layer lli-b. These layers are adjustably connected to move forwards and rearwards relative to each other by fastening elements lill mounted upon the lower layer and 'engaging through slots 5l formed in the upper layer. Leaf springs 52 are also mounted upon the fastening elements and have resilient front ends 52' which are adapted to engage in certain of a plurality of recesses 53 formed in the top layer tile. rod 25 is mounted upon the top layer Hifi The bottom layer itb is provided with the rollers il which operate in the grooves as previously mentioned. The support plate is connected with. the bottom layer ib at thepoints 353% (see Fig. '7). In other respects this form of the invention is identical to the prior form and like parte have been designated by the same reference numerals.

The operation of the form of the device shown in Fig. 7 is as follovs:

The handle 29 may be moved laterally for shifting the carrier lil laterally to transpose the keyboard thereof. When desired the layer llla may be moved forwards or rearwards relative to the layer lilb by pulling or pushing the handle 29. A change of this type will control the distances through which the transmission hammers 34 move the operator hammers 35. This will modulate the piano. Adjustments may thus be made to strike the string harder or not so hard without varying the touch upon the keys of the piano.

While I have illustrated and described the preferred embodiments of my invention, it is to be understood that I do not limit myself to the precise constructions herein disclosed and the right is reserved to all changes and modications v coming within the scope of the'invention as delined in the appended claims.

Having thus described my invention, what I claim as new, and desire to secure by United States Letters Patent is:

l. In a transposition keyboard for pianos, a carrier consisting of a lower layer and an upper layer resting on said lower layer and having elongated slots extending forwards and rearwards of said piano and a plurality of grooves to the front of said slots, means for supporting said lower layer to be movable laterally of said piano, keys mounted on the upper layer of said carrier, a hammermechanism for each of said keys to be actuated by said keys to strike strings stationarily mounted in said piano, said hammer mechanism comprising one section pivotally mounted in said piano and a second section layer resting on said lower layer and having elongated slots extending forwards and rearwards of said piano and a plurality of grooves to the front of said slots, means for supporting said lower layer to be movable laterally of said piano, keys mounted on the upper layer of said carrier, 'a hammer mechanism for each of said keys to be actuated by said keys to strike strings stationarily mounted in said piano, said hammer mechanisms comprising one section pivotally mounted in said piano and a second section mounted on said keys and disposed to the rear of said first section to strike and pivot said rst section to engage its respective string when said keys are actuated, and pins extending from said lower layer through said elongated slots for slidably supporting said upper layer on said lower layer to move forwards and rearwards of said piano and vary the distance between the sections of said hammer mechanisms, and meansron said pins engaging said upper layer for releasably holding said upper layer in various shifted positions on said lower layer.

3. In a transposition keyboard for pianos, a carrier consisting of a lower layer and an upper layer resting on said lower layer and having elongated slots extending forwards and rearwards of said piano and a plurality of grooves to the front of said slots, means for supporting said lower layer to be movable laterally of said piano, keys mounted on the upper layer of said carrier, a hammer mechanism for each of said keys to be actuated by said keys to strike strings stationarily mounted in said piano, said hammer mechanisms comprising one section pivotally mounted in said piano and a second section mounted on said keys and disposed to the rear of said irst section to strike and pivot said rst section to engage its respective string when said keys are actuated, and pins extending from said lower layer through said elongated slots for slidably supporting said upper layer on said lower layer to move forwards and rearwards of said piano and vary the distance between the sections of said hammer mechanisms, and means on said pins engaging said upper layer for releasably holding said upper layer in various shifted positions on said lower layer, comprising a leaf spring for each of said slots, each of said springs having one of its ends mounted on the pin of its respective slot and the other of its ends selectively engageable into one of the plurality of grooves formed to the front of its respective slot.

4. In a transposition keyboard for pianos, a

carrier consisting of a lower layer and an upper layer resting on said lower layer and having elongated slots extending forwards and rearwards of said piano and a plurality of grooves to the front of said slots, means for supporting said anisms comprising one section pivotally mounted in said piano and a second section mounted on said keys and disposed to the rear of said rst section to strike and pivot said rst section to engage its respective string when said keys are actuated, and pins extending from said lower layer through said elongated slots for slidably supporting said upper layer on said lower layer to move forwards and rearwards of said piano and vary the distance between the sections of said hammer mechanisms, and means on said pins engaging said upper layer for releasably holding said upper layer in various shifted positions on said lower layer, comprising a leaf spring for each of said slots, each of said springs having one of its ends mounted on the pin of its respective slot and the other of its ends selectively engageable into one of the plurality of grooves formed to the front of its respective slot, each of said grooves being extended laterally of said piano and arranged one in back of the other.

CARL HAGSTROM. 

